Correct. :victory:St. George?
Nope. Your first answer was a blight on the necrontyr rather than the necrons. And your second answer is not what I was referring to. :no:1:Was it their sun causing solar winds, radiation storms and giving the Necrons a high chance of contracting cancer
2:their infighting and civil wars?
Failures in the tomb worlds 'destroying millions, if not billions of dormant Necrons' would certainly help with the downfall of a race.